IMPORTANT The information provided is of a general nature and should not be used as a substitute for professional advice. If you think you may suffer from an allergic or other disease that requires attention, you should discuss it with your family doctor. The content of the information articles and all illustrations on this website remains the intellectual property of Dr Raymond Mullins and cannot be reproduced without written permission.

General comments
There are many causes of rashes, and most are NOT due to allergy. While there is some overlap between the rashes seen by allergy specialists and skin specialists (dermatologists), as a rule, allergy specialists (such as myself) see people with hives/urticaria, eczema and contact dermatitis and skin “vasculitis” but not other rashes like psoriasis. Dry itchy skin is best seen by a dermatologist, is not likely to have an allergic origin, and allergy testing is unlikely to help. Rashes lasting many weeks at a time are also unlikely to have an allergic cause.

Since wait lists are often long for skin and allergy specialists, the following is useful to do while waiting:

Take photos - sometimes this helps a diagnosis when the rash is well past. Take them to your GP or specialist as a hard printed copy or maybe on a computer flash drive or CD.

Skin biopsy - “if in doubt, chop it out”. If the diagnosis is not clear, your GP can take a small sample of skin (biopsy) and send it to a pathologist for examination. Sometimes this will give an answer.

Take notes and try to answer the following questions - what makes the rash better or worse? when did it start and spread to? how did it last in ONE place before moving around? and what was the total duration? Do antihistamines help a lot, or just a bit and if they do, how quickly do they take to help? Were you on any new medicines or herbal remedies in the weeks leading up to the onset of itch/rash? Have you had this before?

Last reviewed 28 January 2010